[Dnsmasq-discuss] [PATCH] DHCPv6: Add support for more than one hardware address per IPv6 address

Pali Rohár pali.rohar at gmail.com
Fri Jan 1 21:29:46 GMT 2016


On Friday 01 January 2016 21:23:36 Simon Kelley wrote:
> On 23/12/15 21:10, Pali Rohár wrote:
> > This patch allows to assign one IPv6 address for more config
> > entries specified by MAC address. This is similar function as for
> > IPv4 addresses in DHCPv4 server code part.
> 
> This needs some thinking about: DHCPv6 is different from DHCPv4 in
> that clients are not, at all, identified by MAC address, rather by
> client-id and IAID.

I know and this is absolutely uncomfortable for me. One client has 
different DUID across different operating systems. Also different across 
OS reinstalling... Also if I want to connect new device I need to 
instruct people how to set stable DUID across all OS... Just not usable 
for normal usage of "any" device.

For identifying computer/device I need some stable identifier and DHCPv6 
DUID is *not* stable in current implementation of major usage OS.

MAC address of network card is stable. And so this identifier is what I 
prefer to use. dnsmasq has for it support and I'm happy for it! And when 
I configure both DHCPv4 and DHCPv6 one configuration line MAC,ipv4,ipv6 
is really nice for having "clean" configuration.

> In addition, DHCPv6 handles multiple addresses
> and leases per client.

When using just DUID I have problem here. My laptop has both Wifi and 
wired ethernet and with DUID information I'm not able to configure 
dnsmasq for stable ipv6 addresses.

> What's important? To be able to specify more than on MAC address, any
> one of which can be matched, or to have a single IPv6 address which
> is removed from one IAID to another if the MAC addresses are paired?

For specified laptops, I have special configuration. All network 
interfaces (one wifi, one wired ethernet) on those laptops is assigned 
same IP address. Operating system is configured in special way that when 
both interfaces are active it send packets *only* via ethernet.

So it allows me to have active TCP connections and allows me to switch 
between wifi/ethernet without dropping it.

DHCPv4 in dnsmasq has already support for assigning one ip address to 
more MAC addresses (more clients) and this my patch add support for it 
too.

-- 
Pali Rohár
pali.rohar at gmail.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/attachments/20160101/19575d2c/attachment-0001.sig>


More information about the Dnsmasq-discuss mailing list